Duplex Builder Sydney - we are duplex designer and builder who can help you to realize your duplex project.  The following information is relevant for all duplex development.


Duplex home usually consists of two attached dwellings separated with a party wall, garages or other spaces. Duplex can be single storey or double storey. The party wall between the two duplexes need to be built in full height from footing to the underside of roof cladding and is required to be fire rated. Because of fire rating requirement, the party wall is usually built in brick or concrete block. If it is to be built in timber construction, special double stud details with fire rated material in between will need to be adopted. The party wall should also be built to achieve required acoustic rating.


Sometimes duplex home is interpreted as two dwellings in the same building enclosure but one on top of the other. In this case, the floor separating the two duplexes needs to be fire rated and acoustically rated. The staircase serving the upper duplex should be separated from the lower duplex in its own fire rated enclosure or open.


When building duplex homes, duplex builder should provide two separate sets of water supply pipes, waste water pipes, underground drainage pipes, electrical cables and gas pipes. Duplex builder also needs to install separate connection and meters of the above services. Stormwater pipes can be joined up before connection to the street gutter. However, councils usually require stormwater detention system to be installed on site before connection to street gutter.


If an existing house is to be modified to become a pair of duplexes, the duplex builder will need to assess if the existing structure and building services can be altered to accomodate fire rated party wall, or fire rated floor, separate water supply, separate electrical cabling, and separate gas service.


Our duplex building cost ranges between A$1,200 + GST to A$2,500 + GST per sqm of floor area. The actual duplex building cost depends on site condition, design, material and size of project. 

AAPAC DESIGNBUILD is an experienced duplex builder in Sydney and has completed many duplexes, dual occupancies and attached homes projects.  To discuss with us about your duplex development, please contact us on 02-9279 3008, 0414 588 774 or email mail@aapac-designbuild.com

duplex dual occupancy sydney
Now you can multiply the value of your property with confidence

Like so many others who think of developing duplexes on their property, you probably have been puzzled by some of these questions:

  • Can you build duplex on your block?
  • Will you get approval from council for your duplex project?
  • How critical is site width in duplex development? Can you build duplex on narrow block?
  • How big a duplex can you build on your property?  How to maximize your property's potential in terms of duplex development?
  • How much will your duplex project cost you?  How to minimize the cost of building your duplex?
  • Should you buy the advertised duplex development site you come across?  Is it a good opportunity suitable for you?
  • How and where do you start with a duplex development project?
  • Can your existing building be turned into duplex legally?  Can the building be divided technically?
  • What are the important design aspects for your duplex project?

You can now put your mind at ease and develop your duplex project with confidence and certainty by using our professional service. 

With our expertise
and professional experience in feasibility study, design, construction, project management, supervision and development of duplex projects, you will be sure that
  • duplex can be developed on your property (or not)
  • your duplex project will have a better chance in approval by council
  • your duplex project can be built even on narrow blocks (with our innovative design in many cases)
  • your duplex site's development potential is maximized
  • your duplex building cost is trim and unnecessary heavy cost is eliminated through better design
  • your duplex project is feasible and profitable (with our detailed due diligence and vigorous appraisal before you commit to the project)
  • your duplex project is in good guiding old hands